Shipping packaging, padded envelops and envelopes with silicone release liner are particularly popular. Who is not familiar with it: peel off the protective paper strip, glue it and done. The megatrend e-commerce, meaning online shopping, has increased the demand for shipping packaging with the possibility of easy closing and suitability for return shipping. Returns are not uncommon: with online-ordered textiles or shoes, the return rate is 50 percent or more. Depending on the requirements, one or two silicone release liners are applied and usually a tear strip for easy opening.
A widespread solution for self-adhesive closures is double-sided adhesive tape. However, this is costly in procurement and further processing. Adhesive tape rolls have to be replaced at short intervals and thus cause constantly machine downtimes and increased operating effort. Furthermore, the silicone strip is tough to peel and can lead to dissatisfaction of the shipper later on.
A narrow strip of PSA hot melt adhesive is applied using a coating nozzle to a cardboard flap, usually the lid of a packaging. Next, a silicon paper is positioned precisely on the glue trace using a dispenser for protection. The paper strip is usually slightly longer than the underlying adhesive application for easier removal. To ensure that the silicone paper strip can be applied precisely, the adhesive application must be very precise from start to finish. Robatech provides a clean adhesive cut-off even at high machine speeds of 200 m/min. If a tear strip is also applied to the packaging before the silicone release liner, correct positioning of the coating head is particularly important since it can otherwise remove the tear strip.
Unlike an adhesive tape, the amount of adhesive can be adjusted flexibly and simply, depending on the surface and use (corrugated or solid cardboard). This can reduce adhesive consumption and lower costs. Furthermore, the flexible adjustment ensures the correct adhesion for later, secure closure. Settings and format changes are easy and quick via an integrated touch control panel.